Conventionally, there has been known a particulate measurement system which measures the amount of particulates (e.g., soot) contained in a gas under measurement, or target gas (for example, exhaust gas discharged from an internal combustion engine or the like) (see, for example, Japanese Patent Application Laid-Open (kokai) No. 2013-195069).
Such a particulate measurement system includes a particulate sensor which is exposed to the gas under measurement and detects particulates, and a particulate measurement apparatus which is electrically connected to the particulate sensor through a corona cable and controls the particulate sensor.
The particulate sensor includes an ion generation section, an electrification chamber, and a trapping section. The particulate measurement apparatus includes an isolation transformer for corona discharge, a particulate computation section, and a corona discharge control section. The corona cable includes a corona core wire for electrically connecting the ion generation section and the isolation transformer for corona discharge, and a shield wire for covering the corona core wire in a state in which the shield wire is electrically insulated from the corona core wire.
Through use of ions generated at the ion generation section by means of corona discharge, the particulate measurement system electrifies at least a portion of particulates contained in the gas under measurement in the electrification chamber to produce electrified particulates. The particulate measurement system measures the amount of particulates on the basis of a current which flows in accordance with the amount of the electrified particulates discharged from the particulate sensor to the outside.